Ibrahimovic has, however, committed to a new short-term contract with United since stepping up his recovery, with his comeback eagerly-anticipated at Old Trafford.

Jose Mourinho initially suggested that the veteran frontman would not be seen until January, but he is in the Red Devils’ group stage squad for the Champions League and an early return has been mooted.

Fu, though, has warned Ibrahimovic and United against rushing the process, telling the South China Morning Post: “I have no worry about his injury as it always takes time to fully recover.

“In fact the EPL has just started and I am sure Manchester United would not need the player urgently for any crucial game either in the league or European competitions.

“He is very strong but soccer is still a combative sport. As a doctor, of course I want to see him return as slow as possible, only when he is fully fit for the game. There have been many cases of a player returning prematurely with bad consequences.”

Ibrahimovic is not expected to suffer any problems once back to full fitness, with Fu having reiterated that the former Milan, Barcelona and Paris Saint-Germain striker is among the finest physical specimens he has operated on.

He added: "I have treated almost 60 professional players and Ibrahimovic is certainly one of the best and strongest players I have ever operated on.

"He has a very strong attitude. Even before the operation, he firmly believed he would come back in his soccer career and would not retire just because of the injury.

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“And when we examined his knee, other than the ligament injuries he sustained, the joint, the muscles and other parts of his knee are all in top-notch condition, just like those of a 15-year-old boy and not a soccer player who has been [subjecting his knee to the rigours of] fierce physical competition for so many years.

“His operation went very smoothly.”

Ibrahimovic netted 28 times in 46 appearances for United last season, with that haul including match-winning efforts in the Community Shield and EFL Cup final.